Remediation of crosstie cracks

ABSTRACT

The invention relates to a method and sealing agent for sealing cracks in concrete crossties of a railway rail, in particular in concrete crossties of a ballastless track, wherein the cracks have a width equal to or less than 1 mm. According to the invention, a mixture of an epoxy resin binder with quartz sand is used, wherein the quartz sand has a grain size of 0.1 mm to 1 mm.

TECHNICAL FIELD

The present invention relates to a method and a sealing agent forclosing cracks in concrete crossties.

PRIOR ART

Railway crossties are subjected to severe loads. They must therefore bereplaced regularly. This is relatively cost-intensive and in additionleads to relatively long interruptions in the use of the railway track.In particular, in the case of what are called “ballastless railwaytracks”, in which the crossties are cast, an alternative solution forremediation of the crossties is necessary.

It is known to use Icosit®, a 2-component epoxy resin binder, in theform of pourable mortar for fixing bolts and for grouting adhesivejoints having a width of more than 1 cm. Stable epoxy resin mortar isused for sealing rail base plates, bridge bearings and machinefoundations. Icosit® is offered by Sika.

DESCRIPTION OF THE INVENTION

It is an object of the invention to provide a simple, inexpensive andrapid method and a means for remediation of concrete crossties of arailway track.

This object is achieved by a method having the features of claim 1, anda sealing agent having the features of claim 9.

According to the invention, cracks in the concrete crosstie are filledwith a sealing agent which consists of a pourable epoxy resin mortar. Inthis case the mortar is formed from a mixture of an epoxy resin binderwith quartz sand. According to the invention, the quartz sand has agrain size from 0.1 mm to 1 mm. Preferably, the grain size is 0.2 mm to0.7 mm, and more preferably 0.4 mm to 0.7 mm.

The sand used preferably has grains of diameters in the total statedgrain size range. It is, however, also possible that a sand is selected,the grains of which only have diameters in a range smaller than thestated one. Examples thereof are ranges from 0.1 mm to 0.3 mm, 0.2 mm to0.7 mm and 0.5 mm to 1 mm.

It has surprisingly been found that this pourable mortar is suitable forsealing very small cracks in concrete crossties. It has surprisinglybeen found that use of a finer grain size does not lead to a betterresult. The mortar is astonishingly also suitable for cracks, the widthof which is no greater, or insignificantly greater than, the quartz sandgrain size used. For instance, cracks of a width of equal to or lessthan 1 mm, in particular of 0.3 mm, 0.5 mm and 1 mm, may be filled andsealed.

As a result, in particular concrete crossties in ballastless railwaytracks may be promptly remediated and need not be removed from thetrack.

Good results were achieved, when, apart from the binder and the quartzsand, no further component was added. Preferably, the epoxy resin binderand quartz sand are used in a mixing ratio of 1:1 weight percent.

Preferably, the epoxy resin binder is a 2-component agent. Inparticular, Icosit® from Sika has proved itself. Good results wereachieved with Icosit® KC 220/60 TX.

In the method according to the invention, the crack that is to be sealedis preferably dried before it is filled with the mixture. For example, apropane thawing apparatus is suitable for the drying. Preferably, thepourable mortar is applied with a spatula onto and thereby into thecrack, wherein it is spread along the crack.

Further embodiments and variants of the method are given in thedependent claims.

DESCRIPTION OF PREFERRED EMBODIMENTS

Icosit® KC 220/60 TX was mixed with quartz sand of the following grainsizes:

-   a) 0.1 mm to 0.3 mm-   b) 0.2 mm to 0.7 mm-   c) 0.5 mm to 1.0 mm-   d)

The mixing ratio was in each case 1:1 weight percent.

Cracks of 0.3 mm, 0.5 mm and 1.0 mm were filled.

The depth of penetration of the pourable mortar thus mixed was alwaysabout 10 mm. No significant differences were determined.

When the cracks were sealed, the following procedure was followed:

-   a) the cracks to be filled are marked-   b) the construction site is set up-   c) the cracks are, if need be, cleaned and dried using a propane    thawing apparatus-   d) the mortar according to the invention is poured by hand into the    cracks, at an external temperature of +5° C. to +35° C., or applied    with a spatula, and-   e) the sealing compound is reworked, in particular spread with a    spatula. The reworking proceeds immediately after application of the    mortar.

The sealing compound is cured approximately 33 h after processing. Thefilled crossties can, however, be used for traffic immediately aftercompletion of the remediation.

1. A method for sealing cracks in concrete crossties of a railway track,in particular in concrete crossties of a ballastless railway track,wherein the cracks have a width of equal to or less than 1 mm,characterized in that, for the sealing, a mixture of an epoxy resinbinder with quartz sand is used, wherein the quartz sand has a grainsize from 0.1 mm to 1 mm.
 2. The method as claimed in claim 1, wherein agrain size from 0.2 mm to 0.7 mm, in particular from 0.4 mm to 0.7 mm,is used.
 3. The method as claimed in claim 1, wherein epoxy resin binderand quartz sand are used in a mixing ratio of 1:1 weight percent.
 4. Themethod as claimed in claim 1, wherein, as epoxy resin binder, a2-component agent is used.
 5. The method as claimed in claim 1, wherein,as epoxy resin binder, Icosit® is used.
 6. The method as claimed inclaim 5, wherein, as epoxy resin binder, Icosit® KC 220/60 TX is used.7. The method as claimed in claim 1, wherein a crack that is to besealed is dried before it is filled with the mixture.
 8. The method asclaimed in claim 7, wherein a propane thawing apparatus is used for thedrying.
 9. A sealing agent for use in the method as claimed in claim 1,characterized in that the sealing agent consists of a mixture of anepoxy resin binder with quartz sand, wherein the quartz sand has a grainsize from 0.1 mm to 1 mm.
 10. The sealing agent as claimed in claim 9,wherein the quartz sand has a grain size from 0.2 mm to 0.7 mm, inparticular from 0.4 mm to 0.7 mm.
 11. The sealing agent as claimed inclaim 1, wherein epoxy resin binder and quartz sand are present in amixing ratio of 1:1 weight percent.
 12. The sealing agent as claimed inclaim 1, wherein the epoxy resin binder is a 2-component agent.
 13. Thesealing agent as claimed in claim 1, wherein the epoxy resin binder isIcosit®.
 14. The sealing agent as claimed in claim 13, wherein the epoxyresin binder is Icosit® KC 220/60 TX.